<%@ page contentType="image/jpeg;charset=utf-8" import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*" %> 
<%!Color getRandColor(int fc, int bc) {
		Random random = new Random();
		if (fc > 255)
			fc = 255;
		if (bc > 255)
			bc = 255;
		int r = fc + random.nextInt(bc - fc);
		int g = fc + random.nextInt(bc - fc);
		int b = fc + random.nextInt(bc - fc);
		return new Color(r, g, b);
	}%> 
<%
 	out.clear();//这句针对resin服务器，如果是tomacat可以不要这句 
 	response.setHeader("Pragma", "No-cache");
 	response.setHeader("Cache-Control", "no-cache");
 	response.setDateHeader("Expires", 0);
 	int width = 60, height = 20;
 	BufferedImage image = new BufferedImage(width, height,
 			BufferedImage.TYPE_INT_RGB);
 	Graphics g = image.getGraphics();
 	Random random = new Random();
 	g.setColor(getRandColor(200, 250));
 	g.fillRect(0, 0, width, height);
 	g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
 	g.setColor(getRandColor(160, 200));
 	for (int i = 0; i < 155; i++) {
 		int x = random.nextInt(width);
 		int y = random.nextInt(height);
 		int xl = random.nextInt(12);
 		int yl = random.nextInt(12);
 		g.drawLine(x, y, x + xl, y + yl);
 	}
 	String sRand = "";
 	for (int i = 0; i < 4; i++) {
 		String rand = String.valueOf(random.nextInt(10));
 		sRand += rand;
 		g.setColor(new Color(20 + random.nextInt(110), 20 + random
 				.nextInt(110), 20 + random.nextInt(110)));
 		g.drawString(rand, 13 * i + 6, 16);
 	}
 	// 将认证码存入SESSION 
 	session.setAttribute("rand", sRand);
 	out.print(session.getAttribute("rand"));
 	g.dispose();
 	ImageIO.write(image, "JPEG", response.getOutputStream());
 	out.clear();
    out = pageContext.pushBody();
 %>